Download identifying northern utah`s flowering plants

Revised: May 26, 2003
IDENTIFYING
NORTHERN UTAH’S FLOWERING PLANTS
Mary E. Barkworth
An identification key is basically a series of paired statements. After reading both statements of a pair,
you have to decide which of the two applies to your plant. Each statement will either end in a period or in the
name of a group or a plant family, genus, or species. If the statement ends in a period, read the statement
immediately below and its partner, which will have the same number but may appear directly below the first
or some distance (even pages) away.
The keys presented here are based on those in Shaw’s Vascular Plants of Northern Utah, published by
Utah State University Press., but they have been modified in several respects. For instance, they now
accommodate species that have been found in the region since publication of his work as well as additional
species that are grown as garden plants or are used in teaching plant taxonomy at Utah State University. The
language has also been modified, the general goal being to reduce the amount of unfamiliar words
encountered. There is, however, no getting around the fact that describing plants (and, by extension,
identifying them) requires expanding one’s vocabulary. Enjoy it!
Another modification is designed explicitly to assist students in plant taxonomy. The key attempts to
reflect the family treatment in Shaw AND that in Plant Systematics (Judd et al. 2002). The inames in
CAPITAL letters reflect the interpretation of Judd et al. those in italics are those used in Shaw. The names in
CAPITALS are a more accurate reflection of the phylogeny of flowering plants, as this is now understood,
but there are many floras that have stayed with a more traditional family interpretation. The use of both
systems will, it is hoped, assist those learning plant taxonomy in this time of active discussion and research..
A word of warning: These keys are designed to work in northern Utah. The further away you are from
northern Utah, the less likely they are to work, but learning to use these keys will make it easier for you to
work with other keys, including those appropriate for work in other parts of the world. Expect to struggle a bit
when first using a new flora. Every author has his or her own style.
Never forget to enjoy the plants. They are wondrously diverse and, just as you thought you had begun to
appreciate all the different ways they could put their parts together, you will come across one with a new
twist. Have fun!
This key reflects the families as recognized by Shaw, not as recognized in the Judd et al. (2002), the text book
used in Bio 3400 at USU. Most families are similar to those in A Utah Flora (Welsh et al. 1993), but I have
followed Shaw in using the formulaic names for all the families whereas Welsh et al. use the traditional
names when the choice is permitted by the International Code of Botanical Nomenclature. The following
table shows the equivalencies.
Formulaic Name
Traditional (and more descriptive) name
Apiaceae
Umbelliferae
Brassicaceae
Cruciferae
Fabaceae (but Shaw treats Caesalpinaceae and
Leguminosae – which includes the Caesalpinaceae
Lamiaceae
Labiatae
Poaceae
Gramineae
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Revised: May 26, 2003
Decision 1: Is your plant a monocot or not?
Before starting into the formal key for identifying North Utah's plants to family, you need to make an
important decision: Is you plant a monocot or not? To make this decision, use the table below. Base your
decision on at least two of the above characters. There are exceptions to almost every statement, certainly to
all the more easily observed characters.
In traditional treatments, flowering plants were divided into monocots and dicots. It was recognized that
some dicots, particularly dicots that belonged to what were considered primitive families, often had many
monocot characteristics such as perianth parts in multiples of three and scattered vascular bundles. The
explanation was that monocots were derived early on from within the dicots. Current work in phylogeny
supports this interpretation but, if all recognized groups are to be monophyletic, then the old group dicots falls
by the wayside. The dicots that form a single lineage after divergence of the monocots are called Eudicots
(from the Greek prefix eu meaning “true”). There are some families that are thought to have emerged
somewhere around the same time as the monocot lineage that are not eudicots but, for identification purposes,
this does not matter. It is enough to divide the families into Monocot and Non-monocot families. .
MONOCOTS
NON-MONOCOTS (DICOTS)
Perianth parts are in multiples of 3.
Perianth parts usually in multiples of 4 or 5
Primary leaf veins are 'parallel'.
Primary leaf veins are not parallel.
Stems often have a circle of vascular bundles.
Stems have scattered vascular bundles.
Usually do not form branched woody plants
Seeds have a single cotyledon
Primary roots abort; all functional roots are
adventitious.
Pollen grains are monocolpate1 or monocolpate
derived.
GO TO KEY FOR MONOCOTS (Page 12)
1
2
Plants often highly branched and woody..
Seeds have two cotyledons.
Primary roots often do not abort; secondary roots
also formed.
Pollen grains are tricolpate2 or tricolpate derived.
GO TO KEY FOR NON-MONOCOTS (Page 3)
Have one groove. This is not really a useful identification characteristic; treat it as free information.
Have three round grooves. Similarly, this should be regarded as a free but unnecessary tidbit.
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Revised: May 26, 2003
NON-MONOCOT FAMILIES
Shaw: Dicotyledonae (Class Magnoliopsida)
Plants herbaceous or woody; stems with vascular bundles in a ring; primary veins of leaves not parallel,
usually with evident secondary and tertiary forming an evident netlike structure (this is what is meant by
reticulate venation, a phrase often found in textbooks), floral parts usually 4 or 5-merous; pollen typically
tricolpate.
Decision 2: Which Non-monocot group does your plant belong to?
The non-monocot families are divided here into eight groups. This makes identification a bit less
intimidating because the groups are fairly easy to identify. The groups are artificial, being based solely on
their possession of a set of easy identifiable characteristics. That is why the description of each group contains
no more information that the characteristics used to form them.
1. Plants usually yellow, orange, red, or purple-brown or yellow-green and growing on a
coniferous tree as an epiphyte; all plants under this lead are parasitic or saprophytic. .................... Group 1
1. Plants green, usually not evidently parasitic or saprophytic (several plants that key out
here are root parasites but, unless they are carefully dug up, it is not evident that they are
semi-parasitic, receiving some of their nutrition from another plant species).
2. Plants obligate1 aquatics, either floating or, if rooted in soil, the majority of the plant
body underwater........................................................................................................................... Group 2
2. Plants growing in dry or wet places, rooted in soil or on another plant, the majority of
the plant body growing in air.
3. Plants leafless, succulent, usually with several clusters of sharp spines over the
body; stamens many2 and thigmotropic3 ...................................................................... CACTACEAE
3. Plants with leaves, usually not succulent, the bodies without several clusters of
sharp spines; stamens few to many, not thigmotropic.
4. Flowers individually small, without pedicels4, aggregated into heads5 and
surrounded by an involucre6.
5. Stamens 5, their anthers usually united in a ring around the style; leaves
alternate, opposite, or whorled; inflorescences often with radially symmetric
flowers in the center and and bilaterally symmetric flowers on the outside,
sometimes all flowers alike............................................................................... ASTERACEAE
5. Stamens 2-4, their anthers separate; leaves opposite or whorled; flowers all
alike within a head, bilaterally symmetric .......................................................DIPSACACEAE
4. Flowers small or large, usually with pedicels, never both without pedicels and
with an involucre.
6. Plants herbaceous, with milky juice when fresh; flower parts really difficult
to figure out without help; style top lat and pentagonal in shape if a corolla is
present, divided into three branches if no corolla is present.
7. Flowers unisexual, individually hard to identify, grouped together in a
cyathium7; pistillate flowers consisting of a stalked ovary with 3-welldeveloped style branches, the ovary usually visible above the margin of
the cyathium at maturity. ...................................................................... EUPHORBIACEAE
1
Obligate: Absolutely has to be this way. Plants that can survive flooding, or require flooding for a short period of time are not obligate
aquatics. Duckweed is an obligate aquatic. Many families have a few species that are obligate aquatics.
2
Many: To a botanist, this usually means more than twice the number of petals or more than 10.
3
Thigmotropic: Moves toward something that touches it. Poke your finger into the stamens of a cactus and it will be covered with
pollen. Bindweed is also thigmotropic – it helps it climb.
4
Pedicels: Stalk to a flower
5
Heads: See inflorescence diagrams
6
Involucre: Green bracts surrounding or subtending a group of flowers.
7
Cyathium: A cuplike structure that sometimes has a colorful rim that makes it look like a flower; found only in Euphorbia and its
relatives. See inflorescence diagrams.
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Revised: May 26, 2003
7. Flowers bisexual, easy to identify as such, usually in umbels8; pistil with
2 separate ovaries but an unbranched style that ends in a flat, pentagonal
surface .................................................................................................ASCLEPIADACEAE
6. Plants herbaceous or woody, usually without milky juice even when fresh;
flower parts often easy to recognize (wind pollinated plants, which often
have little or no perianth, can be tough in this regard).
8. Perianth9 consisting of only 1 whorl, this usually not colorful, or of two
whorls but the corolla inconspicuous being both small and drab.
9. Plants definitely woody, trees, shrubs, or vines....................................................Group 3
9. Plants herbaceous, sometimes woody at the base.................................................Group 4
8. Perianth with two whorls, the corolla sometimes small but colorful.
10. Corolla of united petals, the whole corolla coming off when one part
of it is tugged......................................................................................................Group 5
10. Corolla of separate petals, the petals coming off individually when
tugged.
11. Corolla and calyx attached to a hypanthium10, the hypanthium
attached to the receptacle or ovary ................................................................Group 6
11. Corolla and calyx attached directly to the receptacle or top of the
ovary.
12. Number of stamens more than twice as many as the petals....................Group 7
12. Number of stamens up to twice as many as the petals ...........................Group 8
Group 1
Plants obviously parasitic or saprophytic, sometimes epiphytic.
1. Plants parasitic on aerial branches of coniferous trees, yellow-green to green; leaves
opposite11 ................................................................................................................................ VISCACEAE
1. Plants parasitic but not on aerial branches of coniferous trees, not green; leaves alternate
or opposite.
2. Stems twining on host plants, vine-like; plants usually orange or yellow....................CUSCUTACEAE
2. Stems erect, not vine-like, yellowish or purple-brown.
3. Corolla bilaterally symmetric; stamens 4; plants 3–25 cm tall ......................... OROBANCHACEAE
3. Corolla radially symmetric or almost so; stamens 5–10; plants 30-60 cm tall ...........PYROLACEAE
Group 2
Plants obligate aquatics.
Many of the families that key out here also key out in other groups because they contain species that are
not obligate aquatics as well as some that are..
1. Submerged leaves dissected into linear or filiform segments; floating or aerial leaves
often quite different in shape.
2. Flowers inconspicuous, borne in the axils12 of leaves or sessile13 in a terminal spike14;
corolla lacking or quickly deciduous.
3. Plants mostly free-floating; roots usually absent ........................................CERATOPHYLLACEAE
8
Umbel: All flowers on pedicels of equal length that are joined to the stem at the same point. See inflorescence diagrams.
Perianth: The two non-reproductive whorls of a lower, the corolla and calyx)
10
Hypanthium: Cuplike or tube like structure formed of undifferentiated perianth tissue but eventually differentiating into a calyx and
corolla. Check for a hypanthium by looking at the underside of the flower. Is the calyx and corolla differentiated at the pedicel (no
hypanthium) or some distance from it (hypanthium present)? If the perianth is attached above the base of the ovary, is there is stretch of
tissue before the calyx and corolla become separate” If yes, there is a hypanthium; if no, there is no hypanthium.
11
Opposite leaves: two leaves at a node, often on either side of the stem.
12
Axil: Angle between the leaf and the stem.
13
Sessile: without a stalk.
14
Spike: Flowers sessile on an elongate axis. See inflorescence diagrams.
9
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Revised: May 26, 2003
3. Plants rooted.........................................................................................................HALORAGACEAE
2. Flowers conspicuous, borne on naked pedicels or peduncles15.
4. Corolla united, bilaterally symmetric ............................................................LENTIBULARIACEAE
4. Corolla with separate petals, radially symmetric...............................................RANUNCULACEAE
1. Leaves all similar, never dissected into linear or filiform segments..
5. Leaves all basal and simple16.
6. Flowers solitary and radially symmetric; perianth composed of several to many
sepals, the inner sepals petal-like and bright yellow; flowers solitary; leaves
strongly cordate17 at the base.............................................................................. .NYMPHAEACEAE
6. Flowers never solitary, bilaterally symmetric; perianth with a distinct calyx and
corolla; sepals 5, green; leaves usually tapering to the base, not strongly cordate...............................
..................................................................................................................... SCROPHULARIACEAE
5. Leaves not all basal or, if so, the leaves trifoliate18.
7. Leaves opposite or whorled19.
8. Corollas conspicuous, blue; flowers in axillary racemes........................ SCROPHULARIACEAE
8. Corollas inconspicuous or lacking; flowers sessile, short-pedicellate, or solitary.
9. Leaves whorled, giving the stem a “bottle-brush” appearance; corolla
lacking; stamen 1 .........................................................................................HIPPURIDACEAE
9. Leaves opposite, sometimes appearing whorled; corolla present or absent;
stamens 1 or 4.
10. Leaves united around the stem at the base, forming a sheath; corolla
with 4 petals; stamens 4........................................................................ CRASSULACEAE
10. Leaves not united around the stem at the base; corolla absent; stamens 1
........................................................................................................ CALLITRICHACEAE
7. Leaves alternate or appearing basal.
11. Leaves simple, entire20 .................................................................................. POLYGONACEAE
11. Leaves either compound or not entire.
12. Leaves trifoliate and appearing all basal ............................................ MENYANTHACEAE
12. Leaves pinnately compound21 or palmately lobed22, more or less evenly
distributed on the stems.
13. Leaves pinnately compound ............................................................. BRASSICACEAE
13. Leaves palmately lobed ...............................................................RANUNCULACEAE
Group 3
Plants woody, trees, shrubs, or vines. Flowers either with only one perianth whorl, deemed to be the
calyx even if colored, or corolla small, drab, and inconspicuous.
1. Plants vines, sometimes growing along the ground.
2. Leaves opposite; stamens and pistils many............................................................RANUNCULACEAE
2. Leaves alternate; stamens and pistils 3-merous ................................................ ARISTOLOCHIACEAE
1. Plants trees or shrubs.
3. Leaves compound
4. Leaves alternate; fruit a nut23 ................................................................................JUGLANDACEAE
4. Leaves opposite; fruit a samara24.
5. Leaflets 3; fruit with two seeds and two wings, one wing per seed, the fruit
eventually separating into two parts ........................................................................ ACERACEAE
15
Peduncle stalk to a flower cluster; pedicels are stalks to individual flowers.
Simple leaves: leaves without leaflets. See leaf structures.
17
Cordate: Heart shaped. See leaf structures.
18
Trifoliate: Divided into three parts.
19
Whorled leaves: three or more leaves attached at the same node. See leaf structures.
20
Entire margins: smooth edged, without teeth or bumps. See leaf structures.
21
Pinnately lobed: lobed and with an elongate central axis, like a feather. See leaf structures.
22
Palmately lobed: lobed around a basal point, like the fingers of a hand. See leaf structures.
23
Nut: Fruit with a hard woody exterior and a single seed inside. See fruit types.
24
Samara: Fruit with wings (thin, membranous margin or extension). See fruit types.
16
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Revised: May 26, 2003
5. Leaflets 3-7; fruit with one seed, the fruit remaining intact, even in great age...........OLEACEAE
3. Leaves simple.
6. Flowers unisexual; pistillate flowers in stiff, cylindrical or spherical
inflorescences; staminate flowers in catkins25 or ball-shaped inflorescences26.
7. Leaves palmately 3-7 lobed but the margins entire; flowers in spherical
inflorescences; fruit an obconic27, 1-seeded achene28 .........................................PLATANACEAE
7. Leaves unlobed or irregularly lobed, the margins serrate29.to dentate30; flowers
in cylindrical to spherical inflorescences; fruit fleshy, resembling a raspberry ........ MORACEAE
6. Flowers bisexual or unisexual, if unisexual the pistillate flowers in various kinds of
inflorescences but not in stiff, globose inflorescences, the staminate flowers often
in catkins.
8. Flowers always unisexual; staminate flowers in catkins.
9. Plants dioecious31; fruit a capsule with numerous seeds, each bearing a tuft
of hairs; all flowers attached individually directly to their inflorescence axis ... SALICACEAE
9. Plants monoecious32; fruit a 1-seeded, winged achene or nut; staminate
flowers attached in clusters to the inflorescence axis; pistillate flowers in
catkins or solitary.
10. Leaf margins usually dentate to serrate; fruit a 2-winged achene or a nut
enclosed in a leafy cylinder derived from 2-3 bracts .................................BETULACEAE
10. Leaves usually lobed but the margins entire; fruit a nut subtended at the
base by a cupule apparently composed of numerous, small bracts fused
into a cuplike structure....................................................................................FAGACEAE
8. Flowers bisexual or unisexual; flowers never in catkins.
11. Leaves opposite or almost so.
12. Leaves palmately lobed and simple; fruit a schizocarpic33 samara
with two seeds................................................................................. ACERACEAE
12. Leaves unlobed, sometimes compound; fruit an achene, drupe, or
a samara with one seed.
13. Leaves with silvery or brown scales; fruit an achene enclosed in the red or
silvery-gray persistent hypanthium ....................................... ELEAGNACEAE
13. Leaves glabrous34; fruit a samara or blackish drupe35 .................... OLEACEAE
11. Leaves alternate.
14. Secondary veins of leaves parallel and conspicuous; leaf bases often
oblique ........................................................................................ ULMACEAE
14. Secondary veins of leaves not parallel, frequently inconspicuous.
15. Hypanthium not present; styles 2-3; fruit a utricle or achene; plants
often in saline habitats ...........................................CHENOPODIACEAE
15. Hypanthium present; style 1, sometimes with well-developed
branches; fruit an achene with a plumose style, or a drupe with 1 or
3 seeds.
16. Style more or less plumose36 in fruit; stamens numerous
....................................................................................... ROSACEAE
16. Style not persistent in fruit; stamens 4 or 5..............RHAMNACEAE
25
Catkins: flexible, elongate inflorescences.
Inflorescence: Cluster of flowers on a branch. See inflorescence types.
27
Obconic: cone-shaped, but with the widest part of the cone furthest from the base of the flower.
28
Achene: Fruit with tough, almost woody, outer wall and a single seed inside that is not hard to separate from the ovary wall. See fruit
types.
29
Serrate: Margins like the teeth of a saw, pointing forward. See leaf structures.
30
Dentate: Margins with teeth that stick more or less straight out. See leaf structures.
31
Dioecious: Plants with unisexual flowers, individual plants with staminate or pistillate flowers but not both.
32
Monoecious: Plants with unisexual flowers, the staminate and pistillate flowers in separate inflorescences but on the same plant.
33
Schizocarpic: splitting at maturity into two or more parts
34
Glabrous: Without hairs or scales.
35
Drupe: Fruit that is fleshy on the outside, containing one or more seeds, the seeds surrounded by a woody wall. See fruit types.
36
Plumose: Feathery, the hairs flexible and wavy.
26
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Revised: May 26, 2003
Group 4
Plants herbaceous; flowers with a single perianth whorl (deemed to be the calyx) or the corolla small,
drab, and inconspicuous.
1. Ovary more or less inferior, partly or wholly fused with the base of the calyx ................ SANTALACEAE
1. Ovary superior, free from the calyx although sometimes surrounded by it.
2. Perianth completely absent; plants with milky juice when fresh ............................. EUPHORBIACEAE
2. Calyx present, often petalloid in appearance; plants without milky juice.
3. Pistils more than 1per flower.............................................................................RANUNCULACEAE
3. Pistil 1per flower.
4. Hypanthium present.
5. Leaves alternate; stipules present........................................................................... ROSACEAE
5. Leaves opposite; stipules lacking.
6. Stamens many; fruit a circumscissile capsule; leaves fleshy .......................... AIZOACEAE
6. Stamens 3-5; fruit an achene; leaves not fleshy ................................... NYCTAGINACEAE
4. Hypanthium absent.
7. Style unbranched.
8. Leaves dentate, often with stinging hairs; calyx not tubular ......................... URTICACEAE
8. Leaves not dentate, without stinging hairs; calyx tubular, petalloid,
subtended by bracts that often form a calyx-like involucre; ................ NYCTAGINACEAE
7. Style branched, at least distally.
9. Leaves deeply palmately 5-7 lobed or compound; flowers unisexual.. CANNABINACEAE
9. Leaves not deeply lobed, always simple; flowers unisexual or bisexual.
10. Fruit a capsule with several to many seeds; leaves opposite... CARYOPHYLLACEAE
10. Fruit a 1-seeded achene or utricle; leaves alternate or opposite.
11. Calyx 3-merous; stamens 3,6, or 9; stipules often forming a
hyaline sheath around the stem................................................ POLYGONACEAE
11. Calyx of 1, 4, or 5 lobes or sepals.
12. Bracts subtending the flowers not scarious; plants often
mealy, scaly or fleshy ................................................... CHENOPODIACEAE
12. Bracts subtending flowers scarious; plants not mealy, scaly,
or fleshy........................................................................ AMARANTHACEAE
Group 5
Plants with united corollas.
To go this route, ALL the petals must be united together into a single structure. None of the members of
the Fabaceae should not be taken through this route because only the lower two petals are fused (and that only
lightly); the remainder are separate.
1. Ovary inferior or partly so
2. Stamens united by their anthers
3. Plants with tendrils ..............................................................................................CUCURBITACEAE
3. Plants without tendrils.......................................................................................CAMPANULACEAE
2. Stamens distinct
4. Leaves alternate; stamens 5...............................................................................CAMPANULACEAE
4. Leaves opposite or whorled; stamens 5 or fewer
5. Flowers bilaterally symmetric
6. Plants herbaceous; stamens 1–3; calyx conspicuous on fruit, essentially
invisible in flower ......................................................................................VALERIANACEAE
6. Plants woody; stamens 4–5; calyx never conspicuous, lobes usually visible
.................................................................................................................. CAPRIFOLIACEAE
5. Stamens 2,4, or 5; flowers usually radially symmetric.
7
Revised: May 26, 2003
7. Ovary 1-loculed; flowers in heads subtended by a whorl or whorls of bracts,
these usually green; fruit an achene
........................................................................................................................ DIPSACACEAE
7. Ovary 2-5-loculed; flowers not in heads; fruit not an achene.
8. Plants herbaceous; ovary 2-loculed; stems square in cross-section................. RUBIACEAE
8. Plants shrubs; ovary 3-5-loculed; stems round in cross-section ........... CAPRIFOLIACEAE
1. Ovary superior
9. Stamens more than 5
10. Petals united almost to the top, urn-shaped or tubular................................................. ERICACEAE
10. Petals united only at the base.
11. Pistils 4-5; plants succulent with simple leaves..............................................CRASSULACEAE
11. Pistils 1; plants not both succulent and with simple leaves
12. Corolla bilaterally symmetric, the petals evidently dissimilar.
13. Petals 4, in 2 dissimilar pairs; sepals 2; leaves dissected ................... FUMARIACEAE
13. Petals 3 but appearing to be 5 because of the 2 petal-like sepals .... POLYGALACEAE
12.Corolla radially symmetric.
14. Flowers small, in dense heads or spikes; fruit a legume ............................FABACEAE
14. Flowers not as above; fruit not a legume.
15. Stamens numerous, united in a tube around the pistil .....................MALVACEAE
15. Stamens 10, united only at the base ............................................ OXALIDACEAE
9. Stamens 5 or fewer (except in Bougainvillea of the Nyctaginaceae, a greenhouse
plant in Utah).
16. Corolla more or less bilaterally symmetric.
17. Fruit of 2-4 nutlets; leaves opposite.
18. Ovary not lobed; style apical, entire .......................................................VERBENACEAE
18. Ovary 4-lobed; style arising from the between the corolla lobes and cleft
at the apex .................................................................................................... LAMIACEAE
17. Fruit a capsule.
19. Ovary 1-loculed; leaves often softly velvety; indoor plants in northern
Utah................................................................................................GESNERIACEACEAE
19. Ovary 2-loculed; leaves seldom velvety; many plants native or able to
persist outside in northern Utah.
20. Seeds winged; placentation parietal; fruit a capsule more than 5
inches long ......................................................................................BIGNONIACEAE
20. Seeds not winged; placentation axile.
21. Stamens 2; calyx with a pair of small bracts at the base; indoor
plant only in northern Utah...................................................... ACANTHACEAE
21. Stamens 2,4, or 5; calyx without any bracts at the base; many
species growing outside in northern Utah..................... SCROPHULARIACEAE
16. Corolla radially symmetric.
22. Ovaries 2 but style and stigma 1; plants often with milky juice (check when
fresh).
23. Stamens visible, the anthers touching each other (but not fused) around
the stigma ............................................................................................... APOCYNACEAE
23. Stamens not evident, the anthers attached to the pistil......................ASCLEPIADACEAE
[The Apocynaceae and Asclepediaceae are closely related and
sometimes treated as a single family which, by the rules that govern the
naming of plants, is called Apocynaceae, that being the older of the two
names].
22. Ovary 1, the style sometimes divided.
24.Ovary with 1 ovule and 1 locule; style and stigma 1; fruit hard, dry;
corolla absent but mimicked by the calyx and an involucre (definitely
one of the more confusing flowers) ...................................................NYCTAGINACEAE
24.Ovary and fruit not as above; both corolla and calyx present
25. Stamens as many as the corolla lobes and opposite them .................PRIMULACEAE
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Revised: May 26, 2003
25. Stamens sometimes as many as the corolla lobes but never opposite
them.
26. Corolla less than 4 mm, scarious, veinless; fruit a
circumscissile capsule ....................................................... PLANTAGINACEAE
26. Corolla and fruit not as above.
27. Ovary 4-lobed; fruit of nutlets, usually 4 but 1-3 abort in
some species; corolla usually with fornices ....................BORAGINACEAE
27. Ovary not 4-lobed; fruit a capsule, berry or drupe.
28. Style with 3 well-developed branches; ovary 3loculed; capsule with 3 valves............................... POLEMONIACEAE
28. Style unbranched or with only 2 branches; fruit not as
above.
29. Sepals 5, separate or united only at the base;
styles 2 or 1, sometimes divided at the top.
30. Plants twining or trailing; corolla pleated in
bud ...................................................... CONVOLVULACEAE
30. Plants erect or diffuse; corolla not pleated in
bud.
31. Petals lined with prominent hairs .. MENYANTHACEAE
31. Petals lacking prominent hairs... HYDROPHYLLACEAE
29. Sepals 4-5, clearly united; style undivided.
32. Ovary with 1 locule ................................... GENTIANACEAE
32. Ovary with 2 or more locules.
33. Stamens 5.................................................SOLANACEAE
33. Stamens 2 or 4.
34. Stamens 2 .............................................. OLEACEAE
34. Stamens 4 .................................... BUDDLEJACEAE
Group 6
Plants with separate petals and separate sepals that are attached, with the stamens, to the top of a
hypanthium.
1. Stamens many, more than twice as many as the petals.
2. Leaves usually alternate, usually with stipules; corolla usually 5-merous; pistils 1many..................................................................................................................................... ROSACEAE
2. Leaves opposite or whorled, without stipules; corolla 4- or 5-merous; pistil 1
3. Stamens attached well down in the hypanthium; corolla usually 5-merous, petals
often wrinkled in bud; plants herbaceous or woody...................................................LYTHRACEAE
3. Stamens attached at the summit of the hypanthium; corolla often 4-merous, petals
not wrinkled in bud; plants woody ....................................................................HYDRANGEACEAE
1. Stamens up to twice as many as the petals, usually 10 or fewer.
4. Corolla bilaterally symmetric; ovary with 1 locule; fruit usually a legume37; all or
most stamens often united by their filaments....................................................................... FABACEAE
4. Corolla radially symmetric; ovary with 1–4 locules; fruit a capsule or berry; stamens
not united by their filaments.
5. Plants herbaceous.
6. Styles 2; ovary often 2-parted near the top ..................................................... SAXIFRAGACEAE
6. Style 1, sometimes branched or lobed distally; ovary never parted distally.
7. Ovary completely inferior, with 4 locules; petals 2 or 4; styles often with 4
branches; stamens 8 .........................................................................................ONAGRACEAE
7. Ovary superior, with 2–4(occasionally 6) locules; styles unbranched; petals
usually 6; stamens 6 or 12 (occasionally 4) ......................................................LYTHRACEAE
37
Legume: dry fruit that splits down both sides. Pea pods are legumes.
9
Revised: May 26, 2003
5. Plants woody.
8. Leaves opposite or whorled; stamens 10 ..................................................... HYDRANGEACEAE
8. Leaves usually alternate; stamens 5, 8, or 10.
9. Petals 4; stamens 8; ovary with 4 locules........................................................ ONAGRACEAE
9. Petals usually 5; stamens usually 5or 10; ovary with 2 locules; fruit a fleshy
berry ......................................................................................................GROSSULARIACEAE
Group 7
Flowers without a hypanthium; petals separate; stamens more than twice as many as the petals.
Members of the Fabaceae do have a hypanthium, but this is often overlooked so they are keyed here as
not having one. There are a few of the families tin Group 6 that are also keyed out in this group because there
hypanthium is often overlooked.
1. Ovary inferior.
2. Flowers bisexual; stems usually rough-hairy (with interesting hairs yet); fruit dry, but
not winged. ........................................................................................................................ LOASACEAE
2. Flowers unisexual; stems smooth and glabrous; fruit and 3-winged. ............................BEGONIACEAE
1. Ovary superior.
3. Plants trees or shrubs, woody.
4. Flower parts spirally arranged ..............................................................................MAGNOLIACEAE
4 Flower parts whorled.
5. Filaments united into a tube around the pistil .........................................................MALVACEAE
5. Filaments separate or in clusters.
6. Leaf blades 3–15 cm long and almost as wide and with saw-toothed,
sometimes doubly toothed, margins....................................................................... TILIACEAE
6. Leaves 0.33–1.5 cm long and 0.1–0.4 mm wide and with smooth-edged
margins.................................................................................................. CROSSOMATACEAE
3. Plants herbaceous or woody only at the base, not definite shrubs
7. Sepals 2, united into a pointed cap in Eschscholzia.
8. Sepals persistent; plants somewhat succulent ................................................PORTULACACEAE
8. Sepals falling off when the flower opens; plants not succulent ....................... PAPAVERACEAE
7. Sepals usually more than 2.
9. Filaments united into a tube around the pistil .........................................................MALVACEAE
9. Filaments separate, not united into a tube.
10. Leaves alternate.
11. Sepals herbaceous, deciduous............................................... RANUNCULACEAE
11. Sepals thick, persistent .......................................................................... PAEONIACEAE
10. Leaves opposite or whorled.
12.Leaves glandular-punctate; style often more than 1 ................................... CLUSIACEAE
12. Leaves not glandular punctate; style 1......................................................... CISTACEAE
Group 8
Plants with separate petals; stamens not more than twice the number of petals
1. Pistils more than 1, nearly or completely separate
2. Plants succulent, particularly the leaves .....................................................................CRASSULACEAE
2. Plants not succulent ............................................................................................... RANUNCULACEAE
1. Pistil 1.
3. Plants climbing by means of tendrils.
4. Fruit fleshy, with a thin skin (a berry); inflorescence a panicle........................................ VITACEAE
4. Fruit dry or with a thick outer skin; inflorescence sometimes a panicle.
5. Fruit dry, a legume, splitting on both sides at maturity; leaves usually
compound ...................................................................................................................FABACEAE
10
Revised: May 26, 2003
5. Fruit fleshy inside but with a tough skin (a pepo), not splitting at maturity;
leaves usually simple ......................................................................................CUCURBITACEAE
3. Plants not climbing by means of tendrils
6. Styles 2-5, separate to near the top of the ovary.
7. Plants definitely woody, trees or shrubs.
8. Leaves small, scalelike, tightly pressed to the branches; flowers minute, in
large clusters ................................................................................................TAMARICACEAE
8. Leaves well-developed, with petioles and not tightly pressed to the branches.
9. Leaves opposite; fruit dry, with 2 wings ....................................................... .ACERACEAE
9. Leaves alternate; fruit fleshy, with one side [this family includes poison
ivy; be careful if there are 3 leaflets] ................................................... ANACARDIACEAE
7. Plants herbaceous.
10. Plants aquatic or on wet mud flats.
11. Leaves more or less finely dissected ............................................ HALORAGACEAE
11. Leaves entire, opposite...........................................................................ELATINACEAE
10. Plants terrestrial.
12. Ovary inferior.
13. Fruit dry, splitting into 2 at maturity; ovary with 2 locules............ APIACEAE
13. Fruit a fleshy berry; ovary with locules .............................................ARALIACEAE
12. Ovary superior.
14. Leaves compound with 3 leaflets....................................................OXALIDACEAE
14. Leaves simple.
15. Sepals 2; leaves basal or cauline ....................................... PORTULACACEAE
15. Sepals 3-5; leaves mostly cauline.
16. Ovary with 1 locule; leaves always opposite ....... CARYOPHYLLACEAE
16. Ovary with 2-5 locules; leaves alternate or opposite ............... LINACEAE
6. Style 1, often dividing into well-defined branches at the top.
17. Ovary inferior .......................................................................................................CORNACEAE
17. Ovary superior, sometimes appearing inferior because closely surrounded by
the hypanthium.
18. Plants woody, trees or shrubs.
19. Corolla bilaterally symmetric, the petals dissimilar.
20. Petals 3..................................................................................... POLYGALACEAE
20. Petals 4-5.
21. Ovary 1-loculed................................................................... FABACEAE
22. Uppermost petal external to the others, often enfolding
them in bud and usually the largest; lowest two petals
connate around the pistil, forming the keel .......................... FABACEAE
22. Uppermost petal internal to the others and often smaller
than them; lowest two petals not connate around the
pistil........................................................................ CAESALPINACEAE
[The above two families are now being put back
together again. The combined families are called either
Fabaceae or Leguminosae; both names are equally
correct]
21. Ovary 3–5-loculed.
23. Leaves pinnately compound ...........................................SAPINDACEAE
23. Leaves palmately compound .............................HIPPOCASTANACEAE
19. Flowers radially symmetric, the petals all alike in size and shape.
24. Leaves compound.
25. Fruit winged.
26. Wing terminal on the seed-containing portion of the
fruit....................................................................................... OLEACEAE
26. Wing extending above and below the seed-containg
portion of the ovary ................................................. SIMAROUBACEAE
11
Revised: May 26, 2003
25. Fruit not winged, a capsule, berry, or legume.
27. Fruit fleshy, not splitting at maturity ........................ BERBERIDACEAE
27. Fruit dry, with 1 locule, splitting down both sides at
maturity...................................................................CAESALPINACEAE
24. Leaves simple, sometimes highly divided but the parts not
separately deciduous.
28. Fruit dry, splitting down both sides at maturity, flattened
.......................................................................................CAESALPINACEAE
28. Fruit fleshy or, if dry, not flat and splitting down both sides
at maturity.
29. Plants trees; leaves alternate. palmately lobed; flowers
in ball-shaped clusters, unisexual .................................PLATANACEAE
29. Leaves neither large nor palmately lobed.
30. Stamens alternate with the petals.........................CELASTRACEAE
30. Stamens opposite the petals
39. Flowers 3-merous; anthers opening by
uplifting valves ........................................... BERBERIDACEAE
39. Flowers 4–5-merous; anthers dehiscing
longitudinally...................................................RHAMNACEAE
18. Plants herbaceous.
40. Sepals 2
41. Flowers radially symmetric; plants succulent ........................PORTULACACEAE
41. Flowers bilaterally symmetric; plants not succulent ................... FUMARIACEAE
40. Sepals 3 or more.
42. Flowers bilaterally symmetric.
43. Fruit with 1 locule, splitting down both sides at maturity;
upper petal the largest, usually enclosing the others in bud;
all or most stamens united by their filaments ..............................FABACEAE
43. Fruit with more than 1 locule, splitting, but not down two
sides, at maturity; petals and stamens not both as above.
44. Leaves with the petiole attached to the center of the
blade.........................................................................TROPAEOLACEAE
44. Leaves with petioles attached to the base of the blades.
45. Sepals 5, none extended as a spur; lowest petal
spurred; ovary 3-loculed .............................................. VIOLACEAE
45. Sepals 3, 1 of which one is extended backwards as
a spur; petals not spurred; ovary 5- or 1-loculed
..........................................................................BALSAMINACEAE
42. Flowers radially symmetric or nearly so.
46. Leaves compound.
47. Leaves opposite, pinnately compound; leaflets 10-16
..............................................................................ZYGOPHYLLACEAE
47. Leaves alternate, palmately or pinnately compound;
leaflets 3-7.
48. Petals 5; stamens 10
49. Stamens all similar in length; leaves pinnately
compound; ovary 5-chambered, the style
elongating conspicuously in fruit.....................GERANIACEAE
49. Stamens in 2 or 3 whorls, the whorls of
different lengths; leaves palmately compound
........................................................................ OXALIDACEAE
48. Petals 4; stamens 6-16
50. Corolla usually bilaterally symmetric; ovary
with 1 chamber, often on a short stalk............ CAPPARACEAE
12
Revised: May 26, 2003
50. Corolla usually radially symmetric; ovary with
two chambers, usually sessile, sometimes on a
short stalk ...................................................... BRASSICACEAE
46. Leaves simple, entire to deeply divided.
51. Sepals 4; stamens 6...................................................... BRASSICACEAE
51. Sepals usually 5, sometimes 3, the filaments sometimes
united at the base.
52. Fruits splitting open, but not into 2 or more units,
at maturity, containing many seeds .......................... PYROLACEAE
52. Fruits splitting into 3–5 individual units at
maturity, each unit containing 1-seed
53. Ovary 3-loculed; the style coming from the
base of the ovary .......................................LIMNANTHACEAE
53. Ovary 5-loculed; the style developing from the
top of the ovary ............................................... GERANIACEAE
Monocot Families
Plants usually herbaceous; stems with scattered vascular bundles; primary veins of the leaves usually
parallel; flowers 3 -merous; pollen monosulcate or monosulcate derived.
Unlike the Dicots, the monocots appear to form a monophyletic group. Many of the characteristics used
to recognize Monocots (see above) are also found in the older dicot families. If in doubt, look for at least two
of the above characteristics before deciding that your plant is a monocot.
1. Plants green disks 1–5 mm in diameter, without stems, leaves, and flowers, floating on
surface of the water or stranded on mud ................................................................................LEMNACEAE
1. Plants with stems and leaves, rooted in soil or floating in water with the bulk of the plant
below the surface of the water.
2. Perianth well-developed, at least the inner segments petalloid in color and texture.
3. Pistils several, the ovaries forming a ring, each ovary with 1 ovule, maturing into a
ring of achenes ...................................................................................................... ALISMATACEAE
3. Pistil 1; fruit a capsule or berry.
4. Leaves stiff, linear linear-lanceolate to linear and sharply pointed, mostly basal .. AGAVACEAE
4. Leaves usually flexible, of varying shapes, not sharply pointed, basal or not.
5. Ovary superior.
6. Sepals green; petals colored; inflorescence subtended by 2 leaf-like bracts
............................................................................................................ COMMELINACEAE
6. Sepals and petals usually similar in color; inflorescence not subtended by
2 leaf-like bracts............................................................................................... .LILIACEAE
5. Ovary inferior.
7. Plants aquatic, the leaves mostly submerged ............................... HYDROCHARITACEAE
7. Plants terrestrial; the leaves not submerged.
8. Flowers radially symmetric or nearly so.
9. Stamens 3 ................................................................................................IRIDACEAE
9. Stamens 6. ............................................................................... AMARYLLIDACEAE
8. Flowers bilaterally symmetric.
10. Stamens attached to the style .........................................................ORCHIDACEAE
10. Stamens attached to filaments ...........................................................CANNACEAE
2. Perianth lacking or reduced, its parts often only scales or bristles, never colorful
11. Leaves linear, sheathing at the base; stamens and pistils partly or completely
concealed by bracts.
12. Leaves usually 2-ranked; stamens and pistil between a pair of dissimilar
bracts.........................................................................................................................POACEAE
13
Revised: May 26, 2003
12. Leaves 3-ranked or reduced to a sheath; stamens and pistil subtended by 1
bract or the pistil completely enclosed in a modified bract, the perigynium38 ..CYPERACEAE
11. Leaves not both linear and sheathing; stamens and pistils not concealed by
subtending scales
13. Plants and flowers floating or submerged, or the flowers raised slightly
above the surface of the water.
14. Flowers bisexual.
15. Tepals 4; stamens 4; plants of fresh water ........................ POTAMOGETONACEAE
15. Tepals lacking; stamens 2; plants chiefly of brackish or alkaline ........ RUPPIACEAE
14. Flowers unisexual.
16. Flowers in globose heads, the lower heads pistillate, the upper
heads staminate ............................................................................SPARGANIACEAE
16. Flowers not in globose heads.
17. Pistils solitary, with 2-4 elongate style branches .........................NAJADACEAE
17. Pistils usually 3-4, each with a short or elongate style .. ZANNICHELLIACEAE
13. Plants of land or shallow water; leaves and flowers usually well above the
surface of the water.
18. Flowers in a dense, elongate spike.
19. Plants 10-40 cm tall; staminate and pistillate flowers intermingled
or flowers bisexual.......................................................................JUNCAGINACEAE
19. Plants 100-200 cm tall; pistillate flowers in lower portion of spike,
staminate flowers in upper portion........................................................ TYPHACEAE
18. Flowers in racemes, open panicles, or ball-shaped clusters.
20. Flowers unisexual, in ball-shaped clusters, the clusters of pistillate
flowers below the clusters of staminate flowers ..........................SPARGANIACEAE
20. Flowers bisexual or staminate and pistillate flowers intermixed,
arranged in racemes, open panicles, or ball-shaped clusters.
21. Flowers in open or ball-shaped clusters; pistil 1.............................JUNCACEAE
21. Flowers in a raceme; pistils 3 or 6, separating at maturity....JUNCAGINACEAE
38
Perigynium: A vase-like bract that completely encircles the pistil, only the styles poking out of the top.
14
Revised: May 26, 2003
A
D
ACANTHACEAE ............................................... 8
ACERACEAE ........................................... 5, 6, 11
AGAVACEAE .................................................. 13
AIZOACEAE ...................................................... 7
ALISMATACEAE ............................................ 13
AMARANTHACEAE......................................... 7
ANACARDIACEAE......................................... 11
APIACEAE ....................................................... 11
APOCYNACEAE ............................................... 8
ARALIACEAE.................................................. 11
ARISTOLOCHIACEAE ..................................... 5
ASCLEPIADACEAE...................................... 4, 8
ASTERACEAE ................................................... 3
DIPSACACEAE.............................................. 3, 8
E
ELATINACEAE................................................ 11
ELEAGNACEAE ................................................ 6
ERICACEAE ....................................................... 8
EUPHORBIACEAE ........................................ 3, 7
F
FABACEAE .................................. 8, 9, 10, 11, 12
FAGACEAE ........................................................ 6
FUMARIACEAE........................................... 8, 12
B
G
BALSAMINACEAE ......................................... 12
BEGONIACEAE............................................... 10
BERBERIDACEAE .................................... 11, 12
BETULACEAE................................................... 6
BIGNONIACEAE............................................... 8
BORAGINACEAE.............................................. 9
BRASSICACEAE ......................................... 5, 13
BUDDLEJACEAE .............................................. 9
GENTIANACEAE .............................................. 9
GERANIACEAE ......................................... 12, 13
GESNERIACEACEAE ....................................... 8
GROSSULARIACEAE ..................................... 10
H
HALORAGACEAE....................................... 4, 11
HIPPOCASTANACEAE................................... 11
HIPPURIDACEAE.............................................. 5
HYDRANGEACEAE.......................................... 9
HYDROCHARITACEAE ................................. 13
HYDROPHYLLACEAE ..................................... 9
C
CAESALPINACEAE.................................. 11, 12
CALLITRICHACEAE ........................................ 5
CAMPANULACEAE ......................................... 7
CANNABINACEAE........................................... 7
CANNACEAE .................................................. 13
CAPPARACEAE .............................................. 12
CAPRIFOLIACEAE ........................................... 8
CARYOPHYLLACEAE ............................... 7, 11
CELASTRACEAE ............................................ 12
CERATOPHYLLACEAE ................................... 4
CHENOPODIACEAE..................................... 6, 7
CISTACEAE ..................................................... 10
CLUSIACEAE .................................................. 10
COMMELINACEAE ........................................ 13
CONVOLVULACEAE ....................................... 9
CORNACEAE................................................... 11
CRASSULACEAE.................................... 5, 8, 10
CROSSOMATACEAE ..................................... 10
CUCURBITACEAE...................................... 7, 10
CUSCUTACEAE ................................................ 4
CYPERACEAE................................................. 13
I
IRIDACEAE...................................................... 13
J
JUGLANDACEAE.............................................. 5
JUNCACEAE .................................................... 14
JUNCAGINACEAE .......................................... 14
L
LAMIACEAE...................................................... 8
LEMNACEAE................................................... 13
LENTIBULARIACEAE...................................... 5
LILIACEAE....................................................... 13
LIMNANTHACEAE......................................... 13
LINACEAE ....................................................... 11
LOASACEAE.................................................... 10
15
Revised: May 26, 2003
RHAMNACEAE............................................6, 12
ROSACEAE.................................................6, 7, 9
RUBIACEAE.......................................................8
RUPPIACEAE ...................................................14
LYTHRACEAE................................................... 9
M
MAGNOLIACEAE ........................................... 10
MAGNOLIOPSIDA .......................................... 3
MALVACEAE .............................................. 8, 10
MENYANTHACEAE ..................................... 5, 9
Monocots........................................................... 13
MORACEAE ....................................................... 6
S
NAJADACEAE ................................................. 14
NYCTAGINACEAE ....................................... 7, 8
NYMPHAEACEAE ............................................ 5
SALICACEAE .....................................................6
SANTALACEAE.................................................7
SAPINDACEAE ................................................11
SAXIFRAGACEAE.............................................9
SCR ......................................................................8
SCROPHULARIACEAE.....................................5
SIMAROUBACEAE .........................................11
SOLANACEAE ...................................................9
SPARGANIACEAE...........................................14
O
T
OLEACEAE .......................................... 5, 6, 9, 11
ONAGRACEAE ............................................ 9, 10
ORCHIDACEAE............................................... 13
OROBANCHACEAE.......................................... 4
OXALIDACEAE..................................... 8, 11, 12
TAMARICACEAE ............................................11
TILIACEAE.......................................................10
TROPAEOLACEAE..........................................12
TYPHACEAE ....................................................14
N
U
P
ULMACEAE........................................................6
URTICACEAE ....................................................7
PAEONIACEAE................................................ 10
PAPAVERACEAE ............................................ 10
PLANTAGINACEAE ......................................... 9
PLATANACEAE .......................................... 6, 12
POACEAE ......................................................... 13
POLEMONIACEAE............................................ 9
POLYGALACEAE........................................ 8, 11
POLYGONACEAE ......................................... 5, 7
PORTULACACEAE ............................. 10, 11, 12
POTAMOGETONACEAE................................ 14
PRIMULACEAE ................................................. 8
PYROLACEAE ............................................. 4, 13
V
VALERIANACEAE ............................................7
VERBENACEAE.................................................8
VIOLACEAE .....................................................12
VISCACEAE .......................................................4
VITACEAE........................................................10
Z
ZANNICHELLIACEAE ....................................14
ZYGOPHYLLACEAE.......................................12
R
RANUNCULACEAE ................................ 5, 7, 10
16